U.S. patent application number 14/559779 was filed with the patent office on 2015-06-25 for powerline communications automotive network.
The applicant listed for this patent is STMicroelectronics, Inc.. Invention is credited to James D. Allen, Huijuan Liu, Oleg Logvinov, Michael John Macaluso, Bo Zhang.
Application Number | 20150180677 14/559779 |
Document ID | / |
Family ID | 53401320 |
Filed Date | 2015-06-25 |
United States Patent
Application |
20150180677 |
Kind Code |
A1 |
Logvinov; Oleg ; et
al. |
June 25, 2015 |
Powerline Communications Automotive Network
Abstract
An embodiment is a powerline communications (PLC) apparatus
including a communications interface that implements a first
communication protocol including of a transceiver that communicates
over an electrical power distribution wiring of a vehicle. The
first communication protocol includes a powerline communications
automotive network (PLCAN) delimiter type (DT) (PLCAN-DT), and a
PLCAN variant length field in a frame control comprising payload
length, a number of symbols used, a PHY block size, and a number of
repetitions used, wherein broadcast addressing is used in the
network to transmit messages.
Inventors: |
Logvinov; Oleg; (East
Brunswick, NJ) ; Zhang; Bo; (Somerville, NJ) ;
Liu; Huijuan; (Bridgewater, NJ) ; Macaluso; Michael
John; (Jackson, NJ) ; Allen; James D.;
(Rochester, NY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
STMicroelectronics, Inc. |
Coppell |
TX |
US |
|
|
Family ID: |
53401320 |
Appl. No.: |
14/559779 |
Filed: |
December 3, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61918511 |
Dec 19, 2013 |
|
|
|
Current U.S.
Class: |
370/390 ;
370/392 |
Current CPC
Class: |
H04L 12/1863 20130101;
H04L 12/1881 20130101; H04L 12/40 20130101; H04L 2012/40273
20130101; H04L 67/12 20130101; H04B 3/542 20130101; H04L 12/40032
20130101; B60R 16/023 20130101; H04L 12/1886 20130101; H04L
2012/40215 20130101 |
International
Class: |
H04L 12/18 20060101
H04L012/18; B60R 16/023 20060101 B60R016/023; H04L 29/06 20060101
H04L029/06; H04L 12/40 20060101 H04L012/40; H04B 3/54 20060101
H04B003/54 |
Claims
1. A powerline communications (PLC) apparatus comprising: a
communications interface that implements a first communication
protocol comprising of a transceiver that communicates over an
electrical power distribution wiring of a vehicle, the first
communication protocol comprising: a powerline communications
automotive network (PLCAN) delimiter type (DT) (PLCAN-DT); and a
PLCAN variant length field in a frame control comprising payload
length, a number of symbols used, a PHY block size, and a number of
repetitions used, wherein broadcast addressing is used in the
network to transmit messages.
2. The PLC apparatus of claim 1, wherein the number of repetitions
is from two to five.
3. The PLC apparatus of claim 1, wherein the PHY block size is from
128 bits to 136 bits.
4. The PLC apparatus of claim 1, wherein the payload length further
comprises more than one payload length, each of the more than one
payload lengths being associated with a different user
identification (ID).
5. The PLC apparatus of claim 1, wherein each powerline bus in the
vehicle comprises a separate PLC network.
6. The PLC apparatus of claim 1, wherein a first priority
resolution slot (PRS) symbol is used to signal an acknowledgment
from a first user.
7. The PLC apparatus of claim 6, wherein a second PRS symbol is
used to signal an acknowledgment from a second user.
8. The PLC apparatus of claim 7, wherein the first and second PRS
symbols are after a last data payload in a first frame and before a
preamble of a second frame.
9. The PLC apparatus of claim 1, wherein the communications
interface is capable of implementing a second communication
protocol.
10. The PLC apparatus of claim 9, wherein the communications
interface is capable of switching between the first and second
protocols based on whether the vehicle is in motion.
11. The PLC apparatus of claim 9, wherein the communications
interface is capable of switching between the first and second
protocols based on location data of the vehicle.
12. A method comprising: transmitting a powerline communication
(PLC) message in a first communication protocol over an electrical
power distribution wiring of an vehicle, wherein transmitting the
powerline communication (PLC) message in a first communication
protocol comprises: transmitting a PLC automotive network (PLCAN)
delimiter type; transmitting the number of times to repeat the
transmission of the PLC message over the electrical power
distribution wiring of the vehicle; transmitting a first payload to
a first user; and transmitting a second payload to a second
user.
13. The method of claim 12, wherein the first payload and the
second payload are a same size.
14. The method of claim 12, wherein the first payload and the
second payload are a different size.
15. The method of claim 12, wherein the PLCAN delimiter type is
transmitted in a PLCAN frame control block, wherein the first and
second payloads are transmitted during a MAC protocol data unit
(MDPU) payload.
16. The method of claim 15, wherein the PLCAN frame control block
is transmitted before the MDPU payload.
17. The method of claim 12 further comprising: transmitting an
acknowledgement from the first user after a last payload has been
transmitted in the PLC message and before a preamble of a next PLC
message; and transmitting an acknowledgement from the second user
after a last payload has been transmitted in the PLC message and
before a preamble of a next PLC message.
18. The method of claim 17, wherein the acknowledgements from the
first and second users are priority resolution slot (PRS)
symbols.
19. The method of claim 12 further comprising: transmitting a
second PLC message in a second communication protocol over the
electrical power distribution wiring of the vehicle.
20. The method of claim 19 further comprising: determining if the
vehicle is in motion; and switching between the first communication
protocol and the second communication protocol based on whether the
vehicle is determined to be in motion.
21. The method of claim 19 further comprising: determining a
location of the vehicle; and switching between the first
communication protocol and the second communication protocol based
on the location of the vehicle.
22. The method of claim 12 further comprising repeating the
transmission of the PLC message at least two times.
23. The method of claim 12, wherein the PLC message is sent using
broadcast addressing.
Description
PRIORITY CLAIM AND CROSS-REFERENCE
[0001] This application claims the benefit of the following
provisionally filed U.S. patent application: Application Ser. No.
61/918,511, filed Dec. 19, 2013, and entitled "Powerline
Communications Automotive Network," which application is hereby
incorporated by reference.
TECHNICAL FIELD
[0002] The present invention relates generally to a means and
apparatus for communicating between vehicle subsystems utilizing
in-vehicle electrical power distribution network.
BACKGROUND
[0003] Modern vehicles (including but not limited to cars, buses,
trains, and planes) consist of many elements, such as sensors,
switches, actuators, motors, displays, and entertainment functions.
For example, FIG. 1 illustrates an example vehicle assembly
including a vehicle 10, a main wiring harness (partial) 20, a
mirror motor 30, a driver door controller 40, a window motor 50, a
driver door key sensor node and window switch node (inside) 60, a
passenger door controller 70, a window motor 80, a passenger door
key sensor node and window switch node (inside) 90, a mirror heater
100, a front door 120, and a passenger door 110.
[0004] The CAN (controller area network) bus was developed in 1983
to allow the different vehicle modules to communicate. The CAN bus
uses four dedicated wires, and an open collector interface so the
number of devices it can support on a bus is electrically limited.
In modern vehicles there may be more than 70 nodes that need to be
connected, and the CAN bus requires multiple bridged CAN networks
in order to exceed the electrical limit. This results in additional
complexity, expense, and weight.
SUMMARY OF THE INVENTION
[0005] An embodiment is a powerline communications (PLC) apparatus
including a communications interface that implements a first
communication protocol including of a transceiver that communicates
over an electrical power distribution wiring of a vehicle. The
first communication protocol includes a powerline communications
automotive network (PLCAN) delimiter type (DT) (PLCAN-DT), and a
PLCAN variant length field in a frame control comprising payload
length, a number of symbols used, a PHY block size, and a number of
repetitions used, wherein broadcast addressing is used in the
network to transmit messages.
[0006] Another embodiment is a method including transmitting a
powerline communication (PLC) message in a first communication
protocol over an electrical power distribution wiring of an
vehicle. Transmitting the powerline communication (PLC) message in
a first communication protocol includes transmitting a PLC
automotive network (PLCAN) delimiter type, transmitting the number
of times to repeat the transmission of the PLC message over the
electrical power distribution wiring of the vehicle, transmitting a
first payload to a first user, and transmitting a second payload to
a second user.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] For a more complete understanding of the present invention,
and the advantages thereof, reference is now made to the following
descriptions taken in conjunction with the accompanying drawings,
in which:
[0008] FIG. 1 illustrates an example vehicle including vehicle
assemblies;
[0009] FIG. 2 illustrates a block diagram of a powerline
communication (PLC) transceiver architecture;
[0010] FIG. 3 illustrates an example of a powerline communication
automotive network (PLCAN) frame format according to an
embodiment;
[0011] FIG. 4 illustrates an example of a PLCAN MAC protocol data
unit (MPDU) frame control block according to an embodiment;
[0012] FIG. 5 illustrates a table of delimiter types for a PLCAN
MPDU frame control block according to an embodiment;
[0013] FIGS. 6A and 6B illustrate a table of the fields for a PLCAN
MPDU frame control block according to an embodiment;
[0014] FIG. 7 illustrates an example of a multi-user MPDU with
fixed-width payloads according to an embodiment;
[0015] FIG. 8 illustrates an example of a multi-user MPDU with
variable-width payloads according to an embodiment;
[0016] FIG. 9 illustrates a time sequence diagram of a typical PLC
signal; and
[0017] FIG. 10 illustrates a time sequence diagram of a PLCAN
signal showing a multi-user acknowledgement according to an
embodiment.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0018] The making and using of embodiments are discussed in detail
below. It should be appreciated, however, that the present
disclosure provides many applicable inventive concepts that may be
embodied in a wide variety of specific contexts. The specific
embodiments discussed are merely illustrative of specific ways to
make and use the invention, and do not limit the scope of the
invention.
[0019] The present disclosure will be described with respect to
embodiments in a specific context, namely a method and apparatus
for a powerline communications (PLC) network used to communicate
between controllers in a vehicle via the vehicle's existing
electrical power wiring.
[0020] As discussed above, a modern vehicle includes many elements,
such as sensors, switches, actuators, motors, displays, and
entertainment functions which need to communicate with each other.
In some cases, these devices may be connected together in
convenient assemblies by function and or location. For example, all
of the door actuators (e.g., door lock actuator), switches (e.g.,
window up/down switch, 90), and motors (e.g., window motor, 80) of
a passenger door (e.g., 110) are all conveniently connected to a
passenger door assembly control module (e.g., 70). The passenger
door assembly control module (e.g., 70) typically consists of a
microprocessor, including a CPU, memory, crystal, and
interfaces/drivers specific to the subsystem element's needs. The
door control module also contains a communications controller means
to communicate between other subassemblies. For example, a switch
(e.g., 60) to open and close a passenger window may be located on a
driver's door and controlled by a driver door assembly control
module (e.g. 40). In this example, the passenger door module and
driver door module have to communicate with each other to complete
the action.
[0021] In accordance with the present disclosure, a powerline
communications (PLC) network is used to communicate between all of
the controllers in the vehicle via the vehicle's existing
electrical power wiring. In this disclosure, the network protocol
is referred to as the powerline communications automotive network
(PLCAN).
[0022] FIG. 2 illustrates a block diagram of a PLC transceiver
architecture. A common technology for PLC is specified in
coexisting and interoperable standards such as the HomePlug Green
PHY Specification, the HomePlug.TM. AV Specification and IEEE Std
1901-2010.TM. ("standards"), which are hereby incorporated by
reference. The HomePlug Green PHY.TM. specification is used in
plug-in electric vehicle DC charging systems, and the standards are
also used in the home and by utilities. Therefore, the PLCAN should
coexist and interoperate with the incorporated standards to avoid
any potential adverse interactions and maximize the application
opportunities.
[0023] The HomePlug Green PHY (HPGP) mini-robust orthogonal
frequency-division multiplexing (OFDM) (mini-ROBO) mode defines a
136-octet frame control PHY protocol data unit (PPDU) payload and
uses quadrature phase shift keying (QPSK) modulation, 917 carriers,
a guard interval of 7.56 microseconds, 1/2 turbo convolution coding
and repeats the message five times (using the robust OFDM) ROBO
interleaver, sometimes referred to as the "repetition" function).
It was specified this way to provide the maximum communications
robustness and longest possible range in noisy channels. Because it
is a small and robust PPDU, it is commonly used to set up a
network, exchange network management messages, and for network
beacon communication. Because PLC is a networked technology, the
number of devices is limited by the network addressability, for
example, HomePlug Green PHY can locally address 2.sup.8 (or 256)
devices and 2.sup.4 (or 16) networks, for a total of 4,096 devices.
As in any network, the practical number of local nodes is also
limited by the amount of traffic the protocol can realistically
support due to data rates and latencies, but this is well in the
range of automotive applications.
[0024] The vehicle application, however, has a different set of
requirements not anticipated by these standards. In the PLCAN
application, there are no hidden nodes, the network size and
configuration is highly stable, the channel noise characteristics
and impedance are highly stable, and the traffic loading is highly
predictable. Therefore, novel changes are presented that optimize
communications for this application, and also reduce the cost and
weight per the automotive industry needs.
[0025] In the preferred embodiment, the mini-ROBO mode is used at
the appropriate time by the PLCAN to talk to (interoperate) with a
standard PLC network. However, to communicate between vehicle
control modules, the PLCAN protocol is used which consists of a new
MPDU frame control delimiter type (DT), a PLCAN-DT (see FIGS. 4 and
5). The PLCAN-DT is not compatible with the standard PLC protocol.
The vehicle can switch between protocols as needed. For example,
the PLC compatible protocol may be used while the vehicle is
parked, but the PLCAN may be used while the vehicle is moving. In
some embodiments, the selection of protocol may also depend on the
vehicle's location, which can be based on location data of the
vehicle. The protocol itself may also be changed depending on the
vehicle's needs. For example, if the rear view camera needs to
transmit an image, higher performance communications may be needed
which may require that other communication protocol parameters be
used. The network may also use the network ID and/or time division
multiple access (TDMA) or frequency division multiple access (FDMA)
techniques to establish independent networks which have different
data rate or latency requirements. For example, the vehicle body
subsystem with its subassemblies, the engine control subsystem, the
entertainment subsystem, and collision avoidance subsystem may have
different network requirements, best addressed by establishing
their own private networks within the vehicle power distribution
system.
[0026] FIG. 3 illustrates an example of a PLCAN frame format
according to an embodiment. The PLCAN frame format includes a frame
control block and a MDPU payload. FIG. 4 illustrates an example of
a PLCAN frame control block according to an embodiment. The
illustrated PLCAN frame control block includes five fields. These
fields are a delimiter type (DT_PLCAN), an access field (ACCESS), a
short network identifier (SNID), a variant field (VF_PLCAN), and a
PLCAN frame control block check sequence (FCCS_PLCAN). FIG. 5
illustrates a table of delimiter types for a PLCAN MPDU frame
control according to an embodiment with the new PLCAN-DT having a
value of 110.
[0027] The PLCAN protocol MPDU frame control block is used to
specify to the receiver, the unique information about the frame,
for example, what type of frame it is, which also affects the
definition of the frame type-dependent fields (variant fields). In
the preferred embodiment both the PHY block size and the ROBO
interleaver repetition can be different from the mini-ROBO size of
136-octet (128-octet PHY block). The preferred embodiment uses two
repetitions to obtain the highest throughput. Three or four
repetitions reduces throughput and increases latency but can be
used to ensure communication reliability.
[0028] FIGS. 6A and 6B illustrate a table of fields for a PLCAN
MPDU frame control according to an embodiment. The PLCAN MPDU frame
control includes different fields over prior art. For example, the
payload length, the number of symbols used, the PHY block size,
and/or the number of repetitions used. The new fields further
include number of users for multi-user communication and the IDs,
payload data length, and payload data type for each of the users.
These new fields can be defined in the Variant Length Field of
Frame Control for the delimiter type of PLCAN, PLCAN-DT. In
addition, the PHY hardware is designed to support the new
delimiter. The channel and ROBO interleavers (and deinterleavers in
the receiver) are also changed to support the fewer number of
repetitions and smaller block size in the PLCAN application. The
Turbo encoder and decoder are designed to yield best reliable
communication on a variable block size, and the smaller block size
also makes small data transfer more efficient. Because the vehicle
power distribution network is physically small, predetermined, and
does not change over time, there are no hidden nodes. Therefore,
all of the traffic can be sent using broadcast mode. That is, all
messages can be broadcast to all the PLCAN controllers on the
network.
[0029] As mentioned above, the PLCAN application also supports
multiple users or messages per payload. That is, the payload can be
divided into sections allocated for specific functions or devices
such as a specific switch's message, or a subsystem message. It can
also be divided by its message content. In this latter case, the
data contains the information such as which data is from which
controller, its destination, and its purpose or content (type). The
MAC layer is responsible for figuring out how to use the data.
[0030] FIG. 7 illustrates an example of a multi-user MPDU with
fixed-width payloads according to an embodiment, and FIG. 8
illustrates an example of a multi-user MPDU with variable-width
payloads according to an embodiment. As illustrated, each PLCAN
frame has four users with each user having their own payload. In
other embodiments, each PLCAN frame can have more or less than four
users.
[0031] In the cited standards, there are also priority resolution
symbols that are sent in priority resolution slots (PRS) that are
used to determine which PLC node has the highest priority traffic.
Nodes contend by sending their request to transmit which contains a
priority value. The lower priority traffic defers to the higher
priority requests and all the higher priority traffic contends for
access using carrier sense multiple access with collision avoidance
(CSMA/CA) methods. During this process, data payload is not
exchanged. Data is exchanged only after a node has permission to
transmit.
[0032] FIG. 9 illustrates a time sequence diagram of a typical PLC
signal and FIG. 10 illustrates a time sequence diagram of a PLCAN
signal showing a multi-user acknowledgement according to an
embodiment. In a preferred embodiment, PLCAN can use the PRS
symbols during the response interframe spacing (RIFS) (see FIGS. 9
and 10) and before the contention interframe space (CIFS) for
acknowledgements (e.g., ACK) for each of the users. In some
embodiments, PLCAN can use other short message types for the
acknowledgements for each of the users. This greatly reduces the
response (latency) time for simple messages as compared to normal
data exchanges or using the contention period. This method is not
compatible with the cited standards and is only available in the
PLCAN mode.
[0033] While this invention has been described with reference to
illustrative embodiments, this description is not intended to be
construed in a limiting sense. Various modifications and
combinations of the illustrative embodiments, as well as other
embodiments of the invention, will be apparent to persons skilled
in the art upon reference to the description. It is therefore
intended that the appended claims encompass any such modifications
or embodiments.
* * * * *